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-rw-r--r--mm/internal.h8
-rw-r--r--mm/mmap.c31
-rw-r--r--mm/mremap.c30
3 files changed, 40 insertions, 29 deletions
diff --git a/mm/internal.h b/mm/internal.h
index 2ab81c68be6c..c61a98d3b3c7 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1005,11 +1005,9 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
/*
* mm/mmap.c
*/
-struct vm_area_struct *vma_merge(struct vma_iterator *vmi,
- struct mm_struct *, struct vm_area_struct *prev, unsigned long addr,
- unsigned long end, unsigned long vm_flags, struct anon_vma *,
- struct file *, pgoff_t, struct mempolicy *, struct vm_userfaultfd_ctx,
- struct anon_vma_name *);
+struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
+ struct vm_area_struct *vma,
+ unsigned long delta);
enum {
/* mark page accessed */
diff --git a/mm/mmap.c b/mm/mmap.c
index e5e50e547ebf..3ea52451623b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -860,13 +860,13 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
* **** is not represented - it will be merged and the vma containing the
* area is returned, or the function will return NULL
*/
-struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
- struct vm_area_struct *prev, unsigned long addr,
- unsigned long end, unsigned long vm_flags,
- struct anon_vma *anon_vma, struct file *file,
- pgoff_t pgoff, struct mempolicy *policy,
- struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
- struct anon_vma_name *anon_name)
+static struct vm_area_struct
+*vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
+ struct vm_area_struct *prev, unsigned long addr, unsigned long end,
+ unsigned long vm_flags, struct anon_vma *anon_vma, struct file *file,
+ pgoff_t pgoff, struct mempolicy *policy,
+ struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+ struct anon_vma_name *anon_name)
{
struct vm_area_struct *curr, *next, *res;
struct vm_area_struct *vma, *adjust, *remove, *remove2;
@@ -2500,6 +2500,23 @@ static struct vm_area_struct
}
/*
+ * Expand vma by delta bytes, potentially merging with an immediately adjacent
+ * VMA with identical properties.
+ */
+struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
+ struct vm_area_struct *vma,
+ unsigned long delta)
+{
+ pgoff_t pgoff = vma->vm_pgoff + vma_pages(vma);
+
+ /* vma is specified as prev, so case 1 or 2 will apply. */
+ return vma_merge(vmi, vma->vm_mm, vma, vma->vm_end, vma->vm_end + delta,
+ vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff,
+ vma_policy(vma), vma->vm_userfaultfd_ctx,
+ anon_vma_name(vma));
+}
+
+/*
* do_vmi_align_munmap() - munmap the aligned region from @start to @end.
* @vmi: The vma iterator
* @vma: The starting vm_area_struct
diff --git a/mm/mremap.c b/mm/mremap.c
index ce8a23ef325a..38d98465f3d8 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1096,14 +1096,12 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
/* old_len exactly to the end of the area..
*/
if (old_len == vma->vm_end - addr) {
+ unsigned long delta = new_len - old_len;
+
/* can we just expand the current mapping? */
- if (vma_expandable(vma, new_len - old_len)) {
- long pages = (new_len - old_len) >> PAGE_SHIFT;
- unsigned long extension_start = addr + old_len;
- unsigned long extension_end = addr + new_len;
- pgoff_t extension_pgoff = vma->vm_pgoff +
- ((extension_start - vma->vm_start) >> PAGE_SHIFT);
- VMA_ITERATOR(vmi, mm, extension_start);
+ if (vma_expandable(vma, delta)) {
+ long pages = delta >> PAGE_SHIFT;
+ VMA_ITERATOR(vmi, mm, vma->vm_end);
long charged = 0;
if (vma->vm_flags & VM_ACCOUNT) {
@@ -1115,17 +1113,15 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
}
/*
- * Function vma_merge() is called on the extension we
- * are adding to the already existing vma, vma_merge()
- * will merge this extension with the already existing
- * vma (expand operation itself) and possibly also with
- * the next vma if it becomes adjacent to the expanded
- * vma and otherwise compatible.
+ * Function vma_merge_extend() is called on the
+ * extension we are adding to the already existing vma,
+ * vma_merge_extend() will merge this extension with the
+ * already existing vma (expand operation itself) and
+ * possibly also with the next vma if it becomes
+ * adjacent to the expanded vma and otherwise
+ * compatible.
*/
- vma = vma_merge(&vmi, mm, vma, extension_start,
- extension_end, vma->vm_flags, vma->anon_vma,
- vma->vm_file, extension_pgoff, vma_policy(vma),
- vma->vm_userfaultfd_ctx, anon_vma_name(vma));
+ vma = vma_merge_extend(&vmi, vma, delta);
if (!vma) {
vm_unacct_memory(charged);
ret = -ENOMEM;